Alliant Insurance Services grew brokerage revenue 14.4% to $5.72 billion in 2025, extending a run of double-digit gains. The company slipped to No. 6 in Business Insurance’s global broker ranking after Brown & Brown moved ahead following a major acquisition. That change in rank puts the distinction between a broker’s underlying growth and the effect of a large transaction in plain view: a company can expand quickly and still lose a place when a rival adds substantial revenue through a deal.
Alliant’s growth rate was below the nearly 30% recorded in the prior year, but its chief executive says expansion remains largely organic. The slower pace deserves attention, though it doesn’t by itself show that the business has weakened. Comparisons with a particularly strong prior year can make growth look less striking, while the source of that growth—new business, acquisitions, or both—helps explain what the headline rate does and doesn’t say.
Construction and reinsurance lead growth
Construction insurance, commercial auto liability and reinsurance were the main contributors, CEO Greg Zimmer said. Reinsurance revenue rose more than 50%, while the nonstandard auto business continued to take market share. Construction also had another strong year. Those results point to growth spread across several areas, though the reported details don’t show how much each one contributed to the total increase.
Alliant’s reinsurance operation is currently focused on facultative business, which generally addresses coverage for individual risks. Zimmer said the company is exploring treaty reinsurance, a different form of coverage that applies to an agreed portfolio of risks. He described it as a significant opportunity, but exploration isn’t the same as an established revenue stream. Building a business in a new part of reinsurance can take time and depends on the company’s ability to attract clients and place coverage.
Zimmer also expects construction to continue outperforming the market. That’s a useful signal about management’s view of the business, but it’s a forecast rather than a reported result. Construction insurance can be tied to the volume and complexity of projects, so continued outperformance will depend on conditions in the markets Alliant serves as well as its ability to win and retain accounts. Employee benefits revenue increased more than 12% in 2025, adding another source of growth alongside property and casualty lines.
Those businesses reflect a broader expansion that has lifted Alliant into the top 10 brokers since its debut in the ranking in 2022. The company marked its 100th anniversary last year. Julie Herman, a New York-based director at S&P Global Ratings, said Alliant’s growth has been substantially organic and profitable, without sacrificing margins. That assessment matters because revenue gains alone don’t establish whether a broker is growing on sound economics; margin performance offers a separate measure of whether the expansion is carrying through to profitability.
S&P upgraded Alliant’s issuer credit rating to “B+” from “B” in May. In the upgrade note, Herman cited profitable growth that had enabled significant deleveraging over the past year and put organic growth at 8.6% for full-year 2025. The difference between that organic figure and the overall revenue increase helps clarify the company’s story: growth was not entirely the result of acquisitions, but the two measures describe different things. Investors and competitors watching the broker should keep that distinction in view.
Talent and acquisitions shape the next phase
Alliant did not make any material acquisitions in 2025, Zimmer said. Its deals were small additions to existing operations, while a pipeline of potential transactions remains active. A pipeline can signal opportunity, but it doesn’t guarantee that transactions will close or contribute meaningfully to revenue. With acquisition activity slowing and the pool of top-tier targets shrinking, the firm’s record of recruiting experienced staff may matter more to future growth, said Timothy J. Cunningham, managing director at Chicago-based investment banking and financial consulting firm Optis Partners.
Cunningham attributed Alliant’s outperformance relative to peers largely to talent recruitment. In brokerage, experienced staff can bring client relationships and specialized knowledge that support new business. That model has limits, too: recruiting can be competitive, and adding people doesn’t automatically translate into profitable growth. If you’re working in this space, the practical question is whether hiring continues to produce durable client relationships as the company gets larger.
The company has hired aggressively from competitors over the years, at times facing litigation over alleged violations of nonsolicitation agreements. This year, Alliant joined other brokers in suing Howden after it recruited several Alliant employees. Those disputes show how closely talent competition can be tied to business strategy in a relationship-driven industry. They also underscore that a recruiting advantage may carry costs and uncertainty; the available account doesn’t establish the outcome of the litigation.
Leadership changes also support the company’s expansion. Peter Arkley became president of Alliant’s national retail brokerage, a new post created to oversee growth. Michael J. Cusack, formerly head of Alliant Specialty, succeeded Arkley as president of the property and casualty division. The appointments create clearer leadership responsibilities as the business grows, though new titles alone won’t show whether execution improves. Results will depend on how effectively the teams coordinate across lines and regions.
Technology and client advice
Zimmer sees artificial intelligence as a way to improve internal efficiency, but he doesn’t expect it to displace brokers handling complex commercial risks. Clients, he said, still want an informed person to help them reach decisions. That view draws a line between automating internal tasks and replacing the judgment involved in advising clients, where coverage choices and risk details can be difficult to reduce to a simple process.
AI may change how brokers handle routine work, but its value to a brokerage will depend on whether efficiency gains improve service or costs without weakening advice. Zimmer’s comments describe Alliant’s expectation, not evidence that the technology has already changed its results. And this is the part most people overlook: a tool can make internal work faster while leaving the client’s need for clear explanations largely intact. Still, the company will have to show how those efficiency gains translate into better performance.
What the growth record signals
For Alliant, the near-term growth case rests on businesses already producing gains—particularly construction, reinsurance and employee benefits—alongside continued recruitment and selective acquisitions. The numbers here are underwhelming only if they’re judged against the prior year’s nearly 30% rate without considering the composition of growth. A 14.4% increase remains substantial, but sustaining it becomes a harder test as the revenue base expands.
The balance between those organic engines and a still-active deal pipeline will shape how the broker sustains growth. Acquisitions could add scale, while recruiting and existing lines may support expansion without large transactions; neither route is assured. Alliant’s rating upgrade and S&P’s assessment of profitable growth provide evidence of progress on credit and operating performance, while the lower ranking shows how relative position can shift when a competitor makes a major acquisition.
More to prove. The next phase will turn on whether Alliant can keep growing profitably, maintain momentum in its leading businesses and convert its exploration of treaty reinsurance and its acquisition pipeline into results.